The clustering of galaxies in the SDSS-III DR9 baryon oscillation spectroscopic survey: Testing deviations fromΛ and general relativity using anisotropic clustering of galaxies

We use the joint measurement of geometry and growth from anisotropic galaxy clustering in the Baryon Oscillation Spectroscopic Survey (BOSS) Data Release 9 (DR9) CMASS sample reported byReid et al. to constrain dark energy (DE) properties and possible deviations from the general relativity (GR). Assuming GR and taking a prior on the linear matter power spectrum at high redshift from the cosmic microwave background (CMB), anisotropic clustering of the CMASS DR9 galaxies alone constrains Ω_m = 0.308 ± 0.022 and 100Ω_k = 5.9 ± 4.8 for w = -1, or w = -0.91 ± 0.12 for Ωk = 0. When combined with the full CMB likelihood, the addition of the anisotropic clustering measurements to the spherically averaged baryon acoustic oscillation location increases the constraining power on DE by a factor of 4 in a flat cold dark matter (CDM) cosmology with constant DE equation of statew (givingw=-0.87± 0.05). This impressive gain depends on our measurement of both the growth of structure and the Alcock-Paczynski effect, and is not realized when marginalizing over the amplitude ofredshift-space distortions. Combining with both the CMB and Type Ia supernovae, we find Ω_m = 0.281 ± 0.014 and 1000Ω_k =-9.2 ± 5.0 for w=-1, or w₀ =-1.13 ± 0.12 and w_a = 0.65 ± 0.36 assuming Ω_k = 0. Finally, when a ΛCDM background expansion is assumed, the combination of our estimate of the growth rate with previous growth measurements provides tight constraints on the parameters describing possible deviations from GR giving γ = 0.64 ± 0.05. For one-parameter extensions ofthe flat ΛCDM model, we find a ~2s preference either for w > -1 or slower growth than in GR. However, the data are fully consistent with the concordance model, and evidence for these additional parameters is weaker than 2σ.